1. Field of the Invention
The present invention relates to a flat panel display device, more particularly, to a method and apparatus for fabricating a flat panel display device.
2. Description of the Related Art
In recent years, the importance of display devices in presenting visual information has increased. In the past, a cathode ray tube was widely used. However, a cathode ray tube is heavy, large and has a bulky profile.
A liquid crystal display (LCD) device, a field emission display (FED) device, a plasma display panel (PDP) and an electro-luminescence (EL) device are flat panel display devices available in the market having a thin profile. The liquid crystal display device is light and its mass production yield is steadily improving. Thus, the liquid crystal display has been rapidly replacing the cathode ray tube in many fields.
A liquid crystal display device of active matrix type, which drives liquid crystal cells by using thin film transistors (hereinafter “TFT”), has excellent picture quality and low power consumption. The active matrix type liquid crystal display device is quickly being developed to have a larger size and higher resolution. Further, mass production technology is increasing the production yield of such a liquid crystal display.
Referring to FIG. 1, the liquid crystal display device of the active matrix type includes a color filter array substrate 22 and a TFT array substrate 23. A polarizing plate 17 is attached on the bottom surface of the TFT array substrate 23. A liquid crystal layer 15 is positioned between the color filter array substrate 22 and the TFT array substrate 23. The liquid crystal display device shown in FIG. 1 represents only a portion of an active matrix type liquid crystal display device. In the color filter array substrate 22, a color filter 13 and a common electrode 14 are formed on the bottom surface of an upper glass substrate 12. A polarizing plate 11 is attached on the top surface of the upper glass substrate 12. The color filter 13 includes color filter layers of red R, green G and blue B colors that transmit lights of particular wavelength bandwidth to display colors corresponding thereto, respectively. A black matrix (not shown) is formed between the color filters 13 adjacent with each other.
In the TFT array substrate 23, data lines 19 and gate lines 18 cross each other. TFTs 20 are respectively formed at the crossings of the data lines 19 and the gate lines 18. In addition a pixel electrode 21 is formed at a cell region defined between the data lines 19 and the gate lines 18. The liquid crystal layer 15 controls an amount of light to be transmitted through the TFT array substrate 23 in accordance with the amount of electric field applied across the liquid crystal layer 15. The polarizing plates 11 and 17 transmit light polarized in one direction, and their polarizing directions cross each other. Light is transmitted through the polarizing plates 11 and 17 via the liquid crystal layer 15 when the liquid crystal 15 is in the 90° TN mode. An alignment film (not shown) is formed on the opposite surfaces of the color filter array substrate 22 and the array TFT substrate 23.
The fabricating process for producing the liquid crystal display of active matrix type includes a substrate cleaning process, a substrate patterning process, an alignment forming/rubbing process, a substrate bonding/liquid crystal injection process, a mounting process, an inspection process, a repair process and the like. The substrate cleaning process removes impurities contaminating the substrate surface of the liquid crystal display. The substrate patterning process is subdivided into the patterning process of the color filter substrate and the patterning process of the TFT array substrate. The alignment film forming/rubbing process coats an alignment film onto each of the color filter substrate and the TFT array substrate and rubs the alignment film with a rubbing wheel. The substrate bonding/liquid crystal injection process bonds the color filter substrate with the TFT array substrate through the use of a sealant and injects liquid crystal and spacers through a liquid crystal injection hole, and then seals the liquid crystal injection hole. The mounting process connects a tape carrier package (TCP) to a pad part of the substrate. The TCP has integrated circuits, such as a gate drive IC and a data drive IC. The drive integrated circuit may also be directly mounted on the substrate by a chip-on-glass (COG) technique in addition to a tape automated bonding (TAB) technique using the TCP. The inspection process includes an electrical inspection conducted after forming signal lines, such as data lines, gate lines and the pixel electrodes on the TFT array substrate, and an additional electrical inspection and a naked-eye inspection conducted after performing the substrate bonding/liquid crystal injection process. The repair process conducts a restoration of a substrate judged to be repairable through the inspection process. The substrate that is judged to be un-repairable through the inspection process is discarded.
In the fabricating method of the flat panel display devices including the liquid crystal display device, a thin film material deposited on the substrate is patterned by a photolithography process. In general, the photolithography process includes a series of photo-processes including a photo-resist coating, a mask alignment, an exposure, a development and a cleaning processes. However, there are problems in the photolithography process in that it requires a long time, wastes photo-resist material and stripping solution, and requires the use of expensive equipment, such as an exposure equipment. In addition, the problems include pattern defects.